The present invention relates to a machine for straightening elongated workpieces and comprising a plurality of driven straightening rolls, preferably arranged in a vertical straightening plane, and turnable about their axes entending normal to the direction a workpiece to be straightened passes through the machine, in which the rolls are provided with profiles substantially corresponding to that of the workpiece to be straightened and in which at least part of the rolls are movable individually or in groups toward the workpiece.
Due to their simplicity and a series of known advantages, straightening machines of this type are widely used. However, a decisive disadvantage of straightening machines of the aforementioned kind consist in that they are able to straighten a workpiece only in one plate. A workpiece which is curved in two planes has therefore to be sent twice through such a straightening machine in order to obtain the desired straightness thereof. Due to this disadvantage such straightening machines are mainly used for straightening of workpieces of rectangular cross-section.
It is however known that workpieces having circular cross-sections, such as rods or wires, are usually curved only in one plane. For this purpose, the above-mentioned straightening machines are also used for straightening of workpiece of circular cross-section.
During such use of a straightening machine, the problem arises to introduce the workpiece into the machine in such a manner that the plane of curvature of the workpiece coincides with the straightening plane of the machine. Such a coordination could up to now be obtained only by the operator, respectively a manipulator. Thereby it was not only essential that the straightening plane coincides with the plane of curvature of the workpiece, but in addition it had to be assured that the curvature has the correct sense relative to the arrangement of the rolls in the straightening machine. If the curvature of the workpiece corresponds to the acting curvature of the second roll of the straightening machine, that is when the existing curvature of the workpiece to be straightened correspond or even surpasses the curvature transmitted to the workpiece in the first bending triangle, then the first bending triangle of the straightening machine will remain ineffective so that the straightening machine will not be fully used.